"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
When the United States was founded, the very idea of a nation premised on democratic principles of freedom and tolerance was viewed by the vast majority of the world as an experiment doomed to fail. Dictatorships, monarchies, and theocracies had for many centuries ruled the world.
My younger sister had kids before I did, and managed to earn a master's degree while raising them as a single parent. Now she's a brilliant second-grade teacher. I'm in awe of her ability to juggle everything and still be a great mother.
